The present invention relates to clutches in general, and more particularly to improvements in clutch disc assemblies which can be utilized in friction clutches for automotive vehicles or the like.
It is already known to provide a clutch disc assembly with a first component having a rotary hub and two annular guides which are spaced apart from one another, which rotate with and which surround the hub, and with a second component which includes a clutch disc disposed between the two guides and carrying the customary friction coatings engageable with the pressure plates of a friction clutch. The clutch disc is rotatable within limits relative to the first component, and the assembly normally further comprises energy storing devices which are installed between the two components to yieldably resist at least the first or initial stage or stages of rotation of the clutch disc relative to the hub. For the sake of simplicity, reference will be had to rotation of the clutch disc relative to the hub with the understanding, however, that the hub can rotate relative to the clutch disc, that the clutch disc and the hub can simultaneously rotate in opposite directions or that the clutch disc and the hub can rotate in the same direction but at different speeds. It is also known to install between the clutch disc and the first component one or more friction generating devices which assist the energy storing devices in resisting rotation of the clutch disc with reference to the hub and/or which serve to oppose only certain advanced stages of rotation of the clutch disc relative to the hub, i.e., they become effective only after the clutch disc has already completed a certain angular movement from its initial or neutral position relative to the hub. The just discussed friction generating means can comprise a so-called load friction disc, one or more friction pads acting between the friction disc and a part of the first component, and preferably also one or more coil springs or other suitable energy storing devices interposed between the friction disc and a part of the first component.
A clutch disc assembly which embodies the afore-discussed structure is disclosed, for example, in East German Pat. No. 130,801. This patent describes an assembly wherein the space between the two guides of the first component accommodates discrete first and second friction generating devices (one for idling and the other for operation under load) which are disposed at the opposite sides of the clutch disc. A so-called load friction unit is mounted on the radially outermost portion of one of the guides, namely, on a guide which resembles a cup and carries a disc serving as a holder for the load friction unit. The timing of activation of the friction unit (namely, the extent of that angular movement of the clutch disc which is necessary to activate the friction unit) is determined by parts which resemble flags or lugs and are provided on the friction disc. The lugs extend through windows which are provided therefor in the clutch disc and cooperate with energy storing devices which oppose rotation of the clutch disc with reference to the hub. The just described clutch disc assembly is bulky, complex and expensive.